Piston actuated air motor valve mechanism



Aug. 3l, 1,948. G. H. PALM 2,448,459y

PISTON ACTATED AIR MOTOR VALVE MECHANISM Filed Nov. l, 1945 4Sheets-Sheet 1 Aug. 31, 1948. G. H. PALM 2,448,459

PISTON ACTUATED AIR MOTOR VALVE MECHANISM Filed Nov. 1, 1943 4Sheets-Sheet 2 Aug. 31, 194s.

G. H. PALM PISTON ACTUATED AIR MOTOR VALE MECHANISM Filed NOV. 1, 1943 4Sheets-Sheet 3 G. H. PALM PIsVIoN ACTUATED AIR MOTOR VALVE MECHANISM fAug. 31, 1948.

4 Sheets-Sheet 4 Filed Nov. l, 1945 Patented Aug. 31, 1948 IISTON`ACTUATED AIR MOTOR VALVE. MECHANISM George H. Palm, Chicago, Ill.,assigner to Stewart- Warner Corporation, Chicago, Ill., a corporationv`of4 Virginia Application November 1, 1943, Serial No. 508.517

2 Claims. 1.

My invention relates to air motors for grease pumps and is particularlyconcerned, but not limited to, an air motor for a grease-pumpwhich ismanually applied to a lubricantdrum of the kind in which lubricant isshipped. from the relinery.

In garages and service stations for lubricating and otherwise. servicingautomobiles, it isl common to utilize a lubricant pump which may beapplied; directly: tothe drum-` or other shipping.

container in, which. lubricantis received from the refinery. Thislubricant pump is manually applied to the lubricant drum andv manuallyremoved` therefrom, after the drum has ,been exhausted oi lubricant.Such grease. pumps' are commonly operated either by electricity or bycompressed air through a iiexible hose or other communication leadingfrom the.` airv pressure tank utilized to inflate tires and for othergeneral purposes.

An object of my inventioniisztoprovide' a: new

andl improved air pump particularly adapted. to"

form part of a grease pump of the foregoing type, wherein the mechanismof the. air motor is. com.;- pact and highly efficient.

Another object of my invention istoV provide an air motor-having a newand improvezdfvalve mechanism.

Another object. of my invention. isv to provide anew and improved valve;mechanism-.for uti.- lization with different types of air. motors;

Another object oi. my invention is toproyide an air motor.; whichutilizesa minimum number.`

of cast parts and/wherein the. various-parts. are designed for minimumexpense irl-manufacture and maximum ease of assembly.

Another object ofA my invention is to provide a new and improved airmotorwhich is durable and: requires a minimum ofv service and where:-`in such service as is required. may be quickly and easily. effected.

Other objects and advantages Willbecome apparent as the descriptionproceeds.

In the drawings:

Fig. 1 is a verticalsectional'view illustrating one preferredembodiment.4 of my invention and is taken-on 1ineI'-I of Fig. 5;

Fig. 2 is a transversesection throughthe air inlet of Fig. 1 and istakenfon line 2;-2of thatyk iigure Fig. 3 is averti'cal sectional-viewof the-valve mechanismand is taken online 3`3of Fig. 1;

Fig. 4 isahorizontal sectionalview ofthe -valve mechanism and istaken'ony line 4--4 oflFig. 1-;

Fig". 5 is a top plan View of the structure shown in Fig. l;

Fig. 6 is a vertical sectional view of a second preferred embodiment ofmy invention;

Fig. 7 is a partial vertical section takenlonvthe line I--l of Fig, 6;

Fig. 8 is a` transverse horizontal section taken on the line 8-8 oi Fig.7 and Fig. 9 is a side View of a guiding sleeve for the valve operatingmechanism.

In the embodiment of Figs. 1 to'5, inclusive, I have. illustrated apreferred form of my invention4 having a single cylinder I 0A Ipressedor otherwise formed of sheet metal and terminating at'its.. lower end inan outwardly extending flange I2V aiixed to a base plate I4 by screws IEor in any other suitable manner. The base plate I4 in turn: is attachedby screws I8` to a cover 2U which is` adapted to overlie the upper endof aA lubricant drum of the kind in which lubricant is shipped from arenery.

A piston 22 is reciprocably arranged in the cylinder I0 and drives apiston rod 24 extending downwardly through an opening in the base I4.

' The lower end ci this piston rod operates the piston oi a lubricantpump which may be of any suitable conventional structure and includes ahousing supported by the tube 26. The upper end of this tube 26 isthreaded at 28 to the lower end of a sleeveV 3B' welded at 32 to thebase. I4. Suitable packing 34 is interposed between the piston rodZilland sleeve 3 to prevent leakageV ofV either air or lubricanttherebetween.y This packing is urged into sealing contact with` the rod2li and sleeve 3l! by a spring 36 supportedon a metal washer 38Yrestingon the upper endof the tube 26. Sealing washers 4U ander are preferablyclamped on opposite sides of the washer 38 to prevent escape oi'lubricant through the.

cover plate 2li and terminate in the usuai fleXio-le discharge hose,provided with a control-valve having a coupler ror establishing aconnection with any ofthe fittings attacnedto the chassis .bearings ofautomobiles.

A sheet metal cup 52 is secured tothe upper end oi the cylinder II) bybolts 54 which screw intoV bosses 55 attached to the upper end of thecylinder IIT. This cup Iihas a threadednipple Elisecured thereto and aflexible conduit 58 connects this nipple with an air pressure tank orother suitab-le source of air supply. In order to prevent escape of airfrom the interior of the cup 52, a sealing washer 50 is interposedbetween the lower end 4of this cup and the upper end of the cylinder l0.

A port assembly .comprising castings 82 and 04 and stop members 66 and68 is held together by screws 1i). This assembly is located in anopening .in a side wall of the cup 52 and is secured in place by a nut12. This port assembly provides an upper port 14, a center port 16 and alower port 18 controlled by a slide valve 80.

The upper port 14 communicates through a passarge 82 with the interiorof a hollow screw 84 which secures one end of a curved pipe 86 (Fig. 5)to the casting 64. This hollow screw 34 has lateral openings 88 whichconnect passage 82 with the interior of the pipe 86. The other end ofthe pipe 86 is connected to the upper end of the cylinder l through vatube S0 (Fig. 3) affixed at its l-ower end to the closed upper end ofthe cylinder |0 and having cross bores 82 communicating with the.interior of the pipe 86. The upper end of the tube 90 is closed by a cap84 which clamps the fitting 96 against the upper end of the cup 52. Theopposite end of the pipe 88 is provided with a similar fitting 88through which the hollow screw 84 passes.

The center port 16 connects with an exhaust passage |00 leading to amuffler indicated generally by reference character |02. This muffleroomprises a sheet metal cup |04 having an integral nipple threaded intothe casting 64. A sheet metal cover |06 closes the open end of the cup|04 and a mass of horse hair or other similar material |08 is confinedbetween the cover and a perforated cup H0. The cup |04 has a pluralityof exhaust outlets ||2 through which exhaust air is discharged toatmosphere.

The lower port 18 connects with a passage ||4 communicating with theupper end of a pipe |16, whose lower end is in communication with thelower end of the cylinder I0, by way of an opening H8 formed in the baseI4 and the interior of a cup |28 welded or otherwise attached to thisbase.

The valve 88 which controls the ports 14, 16 and is of the D slide valvetype having a rear surface engaged by a spool |22. This rear surface ishigh at the vertical center of the valve and tapers both ways from itshigh point, as is clearly shown in Fig. 1. The spool |22 lis mounted ina yoke |24 pivoted to the pins |25 of a pair of discs |28 located intransverse slots |30 formed in the opposite sides of a crosshead |32.This crosshead is telescoped over the upper end of a valve rod |24 andis attached theret-o by a screw |36. A tubular plug |38 threaded intothe base of the cup 52 slidably receives the upper end of the crosshead|82 and serves as a guide therefor.

The free ends of the yoke |24 lle on opposite sides of the valve 80, asclearly shown yin Figure ,4, and prevent la-teral displacement of thisvalve. The closed end of the yoke |24 is -provided with a pin |40 havinga rounded end engaging the rounded bottom `of the flared depression |42formed in a shoe |44. A spring |46 is confined between this shoe and ashoulder |48 of the air inlet nipple 56 and serves to urge the spool |22against the valve 00, The shoe |44 has a tubular extension |50 whichreceives and guides one end of the spring |46.

The valve operating rod |34 passes through an opening |52 in the upperend of the cylinder I 0. This opening is sealed by a hat-shaped sealingmember |54 held in place by the annular shoulder |56 formed in a plate|58 confined between the cup 52 and cylinder I0. The lower end of thisvalve rod passes freely through an opening in the piston 22 and extendsinto a bore |60 formed in the upper end of the piston rod 24. A sleeve|52 is threaded to the lower end of the valve rod |34 and held againstaccidental displacement by a pin |64. The sleeve |62 is larger than theopening in the pist-on 22.

The piston 22 is formed of upper and lower metal plates |66 and |68 heldtogether by screws |10 and clamping a sealing ring |12 therebetween. Theupper end ofthe piston rod 24 has a radial ange |14 located between theplates |66 and |68 {"whereby this piston rod is caused to follow themovement of the piston 22.

Suitable sealing washers |16 are located on opposite sides of thisflange to prevent escape of air ytherepast. Downward movement of thepiston 22 is limited by engagement of the screws |10 with the plate I4,and a sleeve |18 loosely surrounding the valve rod |84 engages the upperend of the cylinder l0 to limit upward movement of this piston.

In the position of the parts as shown in Fig. 1, the valve connects port14 with exhaust port 16 so that the upper end of the cylinder l0 is incommunication with atmosphere through the muffler |02. Air supplied tothe interior of the cup 52 can flow freely into the lower port 18 andthrough passage H4, pipe ||6, cup |20 and opening 8 to the lower side ofthe piston 22. The piston will be moved upwardly by the air pressurebelow it and will produce an upward movement of the piston rod 24. Asthe piston 22 approaches the upper end of its stroke, spool |22 willroll over the backwardly projecting ridge of the exposed surface of thevalve 80 and will wedge this valve downwardly t-o uncover the upper port14 and connect the center air exhaust port 15 with the lower port 18. Inthis position of the valve, air under pressure will be admitted to theupper end of the cylinder by Way of pipe 88 and tube 90, and the lowerend of the cylinder will be connected to the muiiier |02. The resultingdownward movement of the piston 22 will create a corresponding downwardmovement of the piston rod 24 'and such reciprocating movement of thisrod will operate the pump mechanism and cause it to discharge lubricantthrough the pipe 50. As the piston 22 approaches the lower end of itsstr-oke a valve operating spool |22 will move across the hump of thevalve 80 and return it to the positionshown in Fig. 1.

A feature of my invention lies in the'fact that valve 80 is operatedwith a snap action so that,

there is no possibility of this valve stopping in mdposition. As thepiston 22 and valve rod |34 move upwardly from the position shown inFig. 1, the shoe |44 moves upwardly to a slight extent with the yoke|24. It is only as the piston approaches the upper end of its strokethat the spool |22 rolls over the hump of the valve 80 and acts as awedge interposed between the valve 80 and the lip |80 on the upper stop66.,

The full force of the spring |46 is thereupon available quickly to shiftthe valve 80 to its lowermost position in engagement with thecorresponding lip |80 of the lower stop 68. These lips limit verticalmovement of the valve 80 and also prevent pressure exerted by the spool|22 on one edge of the valve from forcing the opv posit'e edge of thevalve away fromthe .casting In the embodiment of my invention shown inFigs. 1 to 5,- inclusive, the snap action valve and its operatingstructure are located above the motor cylinder, whereas in theembodiment of my invention shown in Figs. 6 to 9, inclusive, thecorresponding valve structure is located within the motor cylinder. Inthis latter embodiment of my invention, a cylinder 288 formed of atubular piece of metal is weldedv at 282 to a base 284 secured by screws286 to a plate or head 208 closing the lower end of the cylinder 288. Acover 2|8` for a drum or other suitable lubricant container is attachedto the plate 288 by screws 2|2. The plate 288 has welded or otherwisesecured lthereto a sleeve 38 which supports the lubricant pump housingand which may be identical with the corresponding sleeve of the previousembodiment. This sleevesupports the tubing 26 attached thereto by thethreaded connection 28 and the tubing 28 in turn supports'the housing ofthe lubricant pump.

A composite piston indicated generally by reference character 2| 4 isreciprocable in the cylinder 288 and has apiston rod 2l6 attachedthereto for operating the lubricant pumping mechanism. Packing 34 isinterposed between the piston rod 2|6 and sleeve 38 and is urged intosealing position by the springs 36. As in the previous embodiment thesleeve 38 is provide-d with a bore 3| through which any air or lubricantleaking along the piston rod may Ibe discharged to atmosphere.

The composite piston 2i 4 comprises an upper cup leather 2I8 having adepending ilange 229 engaging the cylinder wall and an upwardlyextending ange 222 slidably engaging a tube 224 welded or otherwisesecured to a cap 226 threaded to the upper end of the cylinder 288. Thecup 2l8 is clamped between a metal annulus 228 and an annular plate 238.An expander 232 of neoprene or other suitable material urges the lip 228ci the cup leather into engagement with the cylinder wall.

The composite piston also includes a second cup leather 234 having aflange 286 engaging the cylinder wall and urged thereagainst by anexpander 238. This cup leather is conned between an annular plate 248and a piston head 242. A guiding sleeve 244 for the valve operatingmechanism is located between plates 238 and 248 and holds these platesin spaced relation. The composite piston is maintained in assembledrelation by bolts 246 which extend through the piston structure and havetheir threaded ends screwed into the head 242.

The upper end of the piston rod 218 is threaded at 248 to the pistonhead 242. The upper end of this rod is provided with a bore 258 which isadapted to telescope with a tube 252 aixed to a block 254 welded orotherwise secured to the cylinder cap 226. Packing 256 is interposedbetween the lower end of the tube 252 and the cylinder head 242 and thispacking is maintained in sealing engagement with the tube and head by aspring 258.

Air is supplied through a pipe 268 which connects the air motor with anair pressure tank or any other suitable source of supply. This pipe isthreaded into the block 254 and communicates with the tube 252. Thelower end of this air supply tube 252 is in open communication with thevalve chest 262 formed between plates 238 and 248 of the compositepiston 2I'4. Communi- 6. cationbetween the valve chest 262 andthe lowerend` of tube 252 is established by way of bores 264, 286i andf268 and aport 218 'formed in the cup leather 234.

The sleeve 244 provides three ports 212, 214 and 216 controlled by aslide valve 218` which may be identical with the valve of the .previousembodiment. The upper port 212 communicates with the upper end of thecylinder by way of the passage 280 and the lower port 216' communicateswith the lower end of the cylinder Iby way ofthe passage 282. The centerport 214 constitutes an exhaust port communieating with atmosphere byway of chamber 284i, passage 286- formed between tubes 224 and 252, andexhaust mulller 288 connected to the upper end of this passage.

The slide valve 218 is shifted by a spool or roller 288mo'unted in oneend of a yoke 292 having side arms located in the double U-sha'ped slots294 formed in opposite sides of the rectangular sleeve 244. Springs 296interposed between the closed end of the yoke and one side of-the sleeve244 urge the spool 298 against the valve 218 and store the energy neededto shift this valve.

The closed endr of the yoke 292 lisi partially surrounded by a U-shapedstrip 28B of sheet metal or other suitable material secured to theclosed end of the yoke 292 and having slightly tapered or flared sidesadapted to be engaged by valve operating pins 388 and 382. Sealingwashers 383 of neoprene or other suitable material prevent leakage of'air 'around these pins. Movement of the valve 218 under the thrust ofsprings 296 is limited by stop members 384 which are provided withextending valve engaging ribs for holding its seat that side of thevalve which is not engaged by spool 218.

In the position of the parts shown in Fig. 6, air under pressure isadmitted to the lower end of the cylinder, whereas the upper end of thecylinder is connected to atmosphere through muffler 238. The pressuredifferential across the piston causes upward movement of the piston 214and piston rod 2id. As the piston approaches the upper end of itsstroke, upper pin 388 engages the cap 228 and prevents further upwardmovement of the right hand end of the yoke 282. As the piston continuesits upward movement the arms of this yoke pivot about the high spots 386in the guiding slots 294 (Fig. 9) and spool 288 is caused to roll overthe ridge of the valve 218. This compresses the springs 286 and as soonas the spool passes above the ridge of the valve, these springs snap theright hand end of the yoke to lowermost position, thereby moving thelower pin 882 downwardly and causing the spool 288 to shift valve 218downwardly.

This reverses the connections so that the upper end of the cylinder isnow connected to the source of air supply and the lower end of thecylinder is connected to atmosphere. The pressure differential acrossthe piston is therefore reversed and the piston moves downwardly untilthe lowerl pin 382 engages plate 288 and prevents free downward movementof the closed end of the valve operating yoke 292. Continued downwardmovement of the piston causes this yoke to pivot about the upper points388 of the guiding slots 294 and causes the spool 288 to roll downwardlyover the ridge of the valve 218. As soon as the spool 298 passes belowthis ridge, the energy in the springs 296 snaps the valve to the upposition show in Figure 6.

From the foregoing description of two embodiments of my invention, itwill be seen that I have provided a new and. improved air motor whichmay assume various forms and wherein simple and effective valveoperating mechanism is provided. This valve operating mechanism is ofthe snap action type and utilizes force stored in a spring to producethe shifting movement of the valve. This force is exerted on a rollerwedge and the construction and arrangement is such that a resilientdrive is substituted for a positive drive and no possible damage can beincurred by the valve or operating parts therefor. The air motor of myinvention is highly efficient as well as simple in construction and anynecessary service can be easily effected, since the air motor is soconstructed that it may be readily disassembled for inspection orrepair.

While I have illustrated and described only two embodiments of myinvention, it is to be understood ,that my invention is not limited tothe particular details shown and described and that my inventionincludes all variations, modications and equivalents coming within thefollowing claims.

I claim:

1. An air motor of the class described, comprising a cylinder, a pistontherein, a port connected to each end of said cylinder, means forsupplying compressed air to said ports, a valve controlling admission ofair to said ports, said valve having a ridged surface provided with anapex, a roller engageable with said surface, a yoke supporting saidroller, a pin rigid with the closed end of said yoke, a plate havinga'depression universally receiving said pin, a spring pressing saidplate against said pin and said roller against said valve, and meansconnecting said yoke and piston to cause said roller to move over saidsurface.

2; An air motor of the class described, compris# ing a cylinder, a valvechest mounted upon the cylinder, means for supplying air under pressureto said valve chest, means providing three valve ports, a connectionbetween one of said ports and one end of said cylinder, a connectionbetween another of said ports and the other end of said cylinder, anexhaust passage connected to the third port, a slide valve movablyengaging said ports, said slide valve having a ridged surface, a yoke, aroller mounted therein and engageable with said surface and cooperatingtherewith to shift said valve, resilient means urging said rolleragainst said surface, a piston in said cylinder, a rod driven by saidpiston, and pivot discs for said yoke carried by said rod.

GEORGE H. PALM.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 61,916 Barden Feb. 12, 186790,479 Baldwin May 25, 1869 107,830 Spooner Sept. 27, 1870 140,309Rogers June 24, 1873 142,292 Stevens Aug. 26, 1873 958,492 Hardy May 17,1910 1,119,425 Guerin Dec. 1, 1914 1,807,231 Weeks May 26, 19311,880,650 Zagst Oct. 4, 1932 1,890,341 Singiser Dec. 6, 1932 2,067,635Harris et al Jan. 12, 1937 2,215,852 Klein Sept. 24, 1940 2,220,339Leathem Nov. 5, 1940 2,269,423 Barks et al Jan. 13, 1942

